The introduction of high power LEDs (light emitting diodes) in emergency warning light devices over the last decade has created a demand for constant modifications to the devices in how the light energy of an LED is harnessed to maximize light beam patterns and intensity. The typical packaging of an LED prohibits the LED alone from being omni-directional and gives the LED a limited critical angle or maximum angle of incidence. In many instances, in order to alter the beam pattern and intensity from an LED light source, it is necessary that secondary optics be used in front of the LED.
In the emergency warning light device industry it is common to place secondary optics in front of the LED according to one of three methods: (1) mold optics into an external housing of the LED light device; (2) employ independent optics over each individual LED; (3) a combination of both (1) and (2).
These three methods, though effective in controlling the beam patterns and intensity of LEDs, have limits in flexibility of design and assembly. In the first method, when molding optics into an external housing of an emergency warning light device, the shape of the optics is restricted by the particular physical parameters of the mold negative cavity being able to be separated from the mold positive cavity. Complex shapes of optics require molds with costly lifts and slides. Additionally, once the molding tool is made, simple low-cost modifications are not possible.
The molding restrictions are also present in method (2) where independent optics are placed over the LED. Placing optics over the LEDs provides flexibility in changing beam patterns or beam intensity by simply changing the individual optic, but this is again limited by the required volume needed for the optic and the types of beam patterns that can be generated.